Plating solutions, and the like, containing metal fluoroborates and fluoroboric acid now enjoy a great deal of popularity in the metal finishing industry. Indeed, in some cases, such as printed circuit manufacture, no viable substitutes for the fluoroborate plating baths are currently available. However, at this time, no effective system is known for waste treatment of spent baths and rinse waters containing fluoroborate. Most current treatment systems for this species function on a simple neutralization followed by discharge. This type of treatment seldom, if ever, accomplishes more than a conversion of the fluoroborate ion to a hydrated boron trifluoride or hydroxyfluoroborate anions. These species when discharged are then free to slowly hydrolyze and release toxic fluoride ion into the environment as hydrofluoric acid.
Indeed, previous work (Tomio Onishi, Bulletin of the Chemical Society of Japan, Vol. 42, No. 1, pp. 127-131, 1969) indicates that fluoroborate discharged into streams, rivers, and ocean waters may require more than a year to undergo complete hydrolysis. Additionally, it is reported in the same study, that conditions of elevated pH and temperature can reduce the time required for complete decomposition of the fluoroborate species to a period of 20 to 30 hours. However, a treatment retention time of this magnitude for fluoroborate hydrolysis is extremely impractical for most operations.
It is therefore an object of the present invention to provide a new and improved process for the hydrolysis of fluoroborate ions.
It is another object of the present invention to provide a process for effectively removing fluoride values from solutions containing fluoroborate compounds.
It is still another object of the invention to provide a process for treatment of spent fluoroborate processing solutions from a metal finishing operation.
A further object is to provide a process for the pollution free disposal of effluents from a metal finishing operation employing fluoroborate solutions.